Two-way jack shaft assembly with dado adapter for portable electric saws



T. w. KLUCK 2,646,090 TWO-WAY JACK SHAFT ASSEMBLY WITH DADO ADAPTER FOR PORTABLE ELECTRIC sAws Filed Sept. 14, 1950 July 21, 1953 la l4 26 sq 20 i 24 3 28 a Fig. .2

A Fig. 3 56' Inventor Theodore W K/uck 1 W mg;

Patented July 21, 1953 TENT OFFICE TWO-WAY JACK SHAFT ASSEMBLY VVITH DADO ADAPTER FOR, PORTABLE ELEC- TRIC SAWS Theodore W. Kluck, Houston, Tex;

Application September 14, 1950, Serial No. 184,885

1 This invention comprises novel and useful improvements in a two-way jackshaft assembly with dado adapter for portable electric saws, and more specifically pertains to a jack shaft assembly specifically capable of replaceably mounting dado or saw wheels upon a for operation thereby.

The principal objects of this invention are to provide an improved portable electric hand saw wherein the jack shaft assembly of the same shall be of a greatly simplified construction having a minimum number of parts; shall be capable of an improved mounting in-the casing of the electric saw; wherein an improved detachable connection is provided for securing saws or dado wheels to the jack shaft assembly; and wherein the jack shaft assembly may be readily inserted into or removed from the casing of the saw,

These, together with various ancillary features and objects of the invention, which will later become apparent as the following description proceeds, are attained by the present. invention,

a preferred embodiment of which has been illustrated, by way of example only, in the accompanying drawings, wherein: 1

Figure l is'a fragmentary vertical central sectional view through a conventional form of portable electric hand saw in which the'improved jack shaft assembly of the present invention has been applied, a saw wheel being mounted thereon;

Figure 2 is a view similar to Figure 1 butwith the saw retainer removed from the jack shaft assembly and the saw blade removed therefrom; and

Figure 3 is a view similar to Figure 1 but showing the manner in which a dado wheel is applied to the jack shaft assembly.

Referring now more specifically to the accompanying drawings, wherein like numerals designate similar parts throughout the various views, it will be seen that the numeral I designates a portion of the casing of any conventional form of portable electric hand saw, this casing being of conventional construction and therefore only such parts of the casing have been illustrated as are necessary to understand'the manner in which the present invention is, to be applied thereto. At one end, thecasing is provided with an integral cup-shaped flange l2 constituting a hood and which, at its extreme end, is providedwith a. plane surface M adapted to be engaged by a similar surface of a saw guard It, the latter being retained upon the casing, as by fastening portable electric hand saw a 2 Claims, (01. ma-155) r z a i screws or the like it. The hood !2, together with the guard 55, overlies the end of the casing i0 and constitutes a guard housing or shield for partially enclosing the end of a saw or dado Wheel to be driven'by the device.

As will be further apparent, the casing i0 is provided with a drive shaft passage 20 in which is suitably journaled, as by bearing members 22, a drive shaft z lwhich may be either connected to or may constitutea part of the armature of electric motor by means of which the portable hand saw is powered; I

.At its extreme end, the drive shaft 24 is provided with a helically splined portion 26 which extends into a chamber 28 constituting and hereinafter referred to as a gearing chamber, Conveniently, the casing i0 is providedwith an inwardly eirtending or shouldered portion 30 which constitutes a seat for receiving a correspondingly shaped bearing bracket 32 which constitutes a closure for, the chamber 28, and which also has a supporting surface 35 constituting astop or sent for receiving the bearing member 22 of the drive shaft .24. 1

The chamber 28 has a fixed end wall 36 formed in the casing Hi, the above mentioned bearing bracket ,32 constituting the other wall of the casing. The fixed end wall 36is apertured to constitute a bearing seat 38, While the bearing bracket 32, in turn, is provided with a bearing receiving recess to from one end of which extends a further axially extending and diametrically reduced recess 42 terminating in a closed end wall G4.

The novel replaceable jack shaft assembly forming an essential part of the present invention is adapted to be journaled in the chamber ligand in the bearing seats 38 and 40 as set forth hereinafter.

Referring now more specifically to Figure 1, it will be seen'that the improved jackshaft assembly for the saw blade consists of a jack shaft 48 having a diametrically reduced inner end 48 which is externally threaded as at 50 and which is provided with a shouldered portion 52. An anti friction bearing assembly 54 is received upon the inner end of the jack shaft 46 and pressed against the shouldered portion 52and retained thereagainst as by a fastening nut 5S engaging the screw-threaded end 50.

- Keyed upon an intermediate portion of the jack shaft 46, as by a key 58, is a gearfill having teethcontinuously meshed with the abovementioned helical splines 26 of the driving shaft.

The gear members '26 and Gil thus constitute a gearing transmission connecting the drive shaft 24 with the jack shaft assembly.

The bearing assembly 54 on the inner end of the jack shaft is seated in the bearing seat 40, while the inner end of the jack shaft extends into the previously mentioned recess 42 in the bearing bracket 32.

The jack shaft 46' is further provided; with a bearing surface 62 upon which is mounted an anti-friction bearing assembly 64, the latter be.- ing seated in the above-mentioned bearing seat 38 in the end wall 36 of the casing.

At its outer end, the jack shaft 45 is provided with an internally threaded bore 66 and adjacent this bore is further provided with a laterally en larged annular flange 68 which has a bearing surface HI adapted to abut the outer surface of the casing [0, as clearly indicated in the figures. of the drawings.

The outer end of the jack shaft, surrounding the internally threaded bore 66 is provided with or'constitutes a hub portion 12 which is adapted to receive the apertured portion 14, see Figure 2, of disk saw 76, or of a dado wheel l8, see Figure- 3, or any other implement adapted to be mounted upon the jack shaft assembly and rotated thereby.

As will be readily seen from Figure 2, the extreme outer end of the jack shaft assembly terminates closely adjacent the end wall of the casing H3 and is disposed within and is overlaid by the hood l2 and the guard 16.

In order to detachably secure the saw blade l6 or the dado wheel 18 to the end of the jack shaft, a. retainer is provided. For retaining the saw blade upon the jack shaft, the retainer shown in Figure 1 is utilized. This retainer consists of a central portion. comprising an externally threaded axial extremity 8!] having a rounded ball end adapted to be screw-threadedly engaged in the internally threaded bore socket therein for receiving the rounded end, and an outer axial extension 82 which may conveniently be provided with a socket or recessed opening 84 adapted to. accommodate a wrench or the like. The fastening. means further includes an annular flange 86 which is complementary to the flange 58 and is adapted to frictionally engage and clamp the saw blade. 18 therebetween. The flange 85, however, is provided with an axial recess or chamber as which surrounds the externally threaded extension 80, this chamber or recess slidably receiving and accommodating the hub. portion 12 of the jack shaft.

7 It will. thus be apparent that by the retaining means the saw blade is retained and positioned upon the hub portion 12 and is frictionally engaged by the adjacent complementary surfaces of the flanges 8B and 68.

However, easy access may be had to the retainer from the open end of the hood and guard for releasingthe retaining means and removing the saw, as suggested in Figure 2.

Alternatively, other disks or tools ofgreater width may be quickly and easily attached to the jack shaft "assembly in, place of the saw blade without the necessity of removing the guard It. In order to accomplish this, a longer jack shaft is required. Thus, as shown in Figure 3, a dado wheel 18 may be mounted. upon the jack shaft by means of. the dado adapter, which consists of an externally threaded bolt 90., having a diametrically reduced, externally threaded inner portion 66 having a cup-shaped with a ball pivot 92, received in the above-mentioned internally threaded bore with ball socket 66, and having at its outer end a shouldered socket or recess 94 for the reception of a. wrench or the like. On the above-mentioned externally threaded bolt 90 there is provided an annular retaining flange 96 which is slidably received upon the bolt 90- and is removably or releasably clamped upon the dadowheel 18 for securing the same against the retaining flange 68 of the jack shaft, as by a lock nut 98. By means of this adapter, suificient strength with minimum friction is afforded to permit the use of dado blades and other tools of varying width up to 1% of an inch.

Also, by means of this easily removable and replaceable dado adapter, the shorter retainer comprising the above mentioned externally threaded axialextremity so is easily and quickly exchanged without the necessity of removing the saw guard lb The shorter retainer is required for close work and for sawing vertical angles, since the longer jack shaft retainer would extend out beyond the saw guard l6 and interfere with close Work and, with sawing vertical angles.

From the foregoing, it will beapparent that there is provided a greatly simplified construction of a jack. shaft assembly, and one which is particularly characterized by the adequate bearing means for journaling the same, the detachable bearing bracket which serves both as a closure for the gear chamber and also as a bearing member for the jack shaft; and which provides animproved. meansrfor quickly attaching or removing saw disks or dado wheels, as desired.

Since, from the foregoing, the construction and advantages of this invention are readily apparent, further. description is believed to be unnecessary.

However, since numerous modifications and equivalents will readily occur to those skilled in the art after a consideration of the foregoing specification and accompanying drawings, it is not intended to limit the invention to the exact embodiment shown and described, but all suitable modifications and equivalents may be resorted to which fall within the. scope of the appended claims.

Having. described the claimed as, new is:

1. In a portable electric hand tool having a casing with an electric motor and a jack shaft assembly mounted in the. casing and operatively connected to said electric motor, said assembly including a jack shaft internally threaded at its. outer end, and a hood on the casing overlying the outer end of the jack shaft, the improvement comprising a dado mounting including a, bolt having a threaded reduced end to be secured in the outer end of the jack shaft, the outer end of said bolt being threaded, an annular retaining flange slidable upon said bolt to releasably' clamp a dado blade, and a lock nut on the threaded outer end of the bolt to secure the flange and blade in place.

2. In an electric hand tool having a casing, a jack shaft assembly mounted in said casing, a power connection to said jack shaft, said shaft protruding: from said casing, a hood on said casing and. a tool guard secured to said hood, a tool mounting comprising an annular flange on said invention, what is jack shaft adapted to abut the outer surface of the casing, an internally threaded hub extending axially from. said flange, an enlarged annular tool engaging face.- on said flange, a hub extension in.-

tension;

eluding a diametrically reduced, externally threaded portion received in said internallythreaded hub, a tapered seat in said hub, a ball pivot on the end of said externally threaded portion, said ball pivot seating on said seat when said extension is secured on said hub, an external thread on the outer end of said extension, an annular retaining flange slidably received on said hub, a, nut threadedly mounted on said hub extension; a socket in the end of said hub ex- THEODORE W. KLUCK.

References Cited in the file of this patent Number 5 1,794,758 1,900,553 2,014,229

UNITED STATES PATENTS 

